MAINTENANCE 4.12 EVERY 1000 OPERATING HOURS OR EVERY 6 MONTH 4.12.4 SIGNAL HORN COMPRESSOR - CLEAN AND LUBRICATE See illustration Z 9543 Unscrew collector protection cap (2). Unscrew ball bearing cover and fill it half way up with grease. If the fins of the collector are very strongly blackened or coated with verdigris, clean them with emery cloth. 433